1. Field of the Invention
This invention relates generally to input and output (I/O) subsystems of processing systems, and relates particularly to an interface for coupling I/O devices to a processing system and for buffering data transfers between the I/O devices and the processing system.
2. Description of the Related Art
Data transfers that typical I/O devices are capable of performing are generally slow and piecemeal relative to data transfers that can be performed by other portions of a processing system, such as a CPU or a main memory. To the extent that these other portions must wait on or participate in I/O data transfers, the transfers adversely impact the performance of the processing system. The art therefore needs a mechanism to improve the speed and size of I/O transfers, in order to improve processing system performance. For cost reasons, it is desirable that this mechanism be simple and that its use be shared by a plurality of I/O devices.